import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

public class day05 {

    public static void main(String[] args) {


        ArrayList<String> arr=new ArrayList<>();
        Collections.addAll(arr,"java","python","IT","java","全栈","java");

        Set<String> brr=new HashSet<>(arr);
        System.out.println(brr);
    }
}
